Fix crawler assert of 2 lifetimes with same bytecode reg

The optimization copy-proping away argument object references in inlinees was missing a isJitOptimizeReg flag.
VSO bug: 20813519
diff --git a/lib/Backend/BackwardPass.cpp b/lib/Backend/BackwardPass.cpp
index 6b4c9f9..dabe210 100644
--- a/lib/Backend/BackwardPass.cpp
+++ b/lib/Backend/BackwardPass.cpp
@@ -4059,6 +4059,7 @@
                         Assert(currFunc->HasStackSymForFormal(value));
                         StackSym * paramStackSym = currFunc->GetStackSymForFormal(value);
                         IR::RegOpnd * srcOpnd = IR::RegOpnd::New(paramStackSym, TyVar, currFunc);
+                        srcOpnd->SetIsJITOptimizedReg(true);
                         instr->ReplaceSrc1(srcOpnd);
                         this->ProcessSymUse(paramStackSym, true, true);